The present invention relates to a range switching apparatus used for switching a drive range of, for example, an automatic transmission.
Conventionally, a range switching apparatus for switching a drive range of an automatic transmission, for example, which has a structure constituted by a valve for switching the drive range within the transmission, for example, a manual valve, and a shift lever connected to the valve by a shift cable and provided within a vehicle cabin has been known. The apparatus is structured such as to switch the manual valve via the shift cable in accordance with an operation by a driver applied to the shift lever.
However, in view of requests for expanded freedom of design within the vehicle cabin in recent motor vehicles, requests for expanded derivative types of motor vehicles produced from the same platform and the like, there is a trend that the expansion of freedom of placing the shift lever is becoming necessary. Accordingly, since the shift cable connecting the shift lever and the manual valve is restricted in view of its layout, the development of a range switching apparatus using no shift cable is desired.
Accordingly, there has been proposed in Japanese Utility Model Publication No. HEI 7-16067 and the like a range switching apparatus in which a range switching operation is performed by using an electric motor and an electromagnetic clutch.
The range switching apparatus has two motors comprising first and second motors, and a planetary gear mechanism. The first motor is connected to a sun gear in the planetary gear mechanism via a worm gear and a clutch. The second motor is connected to a planetary gear via a worm gear. Generally, the structure is made such that the second motor is stopped, a plurality of planetary gears do not move around the sun gear, and a torque of the first motor can be output from a ring gear surrounding a plurality of planetary gears and engaged with the planetary gears. The structure is made such that the output torque is further transmitted to a range control shaft (a shaft connected to the manual valve) via a speed reduction mechanism. Further, the second motor is structured such as to be driven when the first motor fails; however, since the first motor and the second motor are interlocked with each other via the planetary gears, they are not affected by one other.
Further, a range switching apparatus provided with a function of detecting a switching position of the manual valve is disclosed in Japanese Patent No. 2904290. This range switching apparatus is also structured so as to switch the manual valve in the automatic transmission by a motor. Further, an electromagnetic clutch is provided between the motor and a manual valve. Further, a position sensor for detecting the switching position of the manual valve is provided in the motor.
However, the range switching apparatus disclosed in Japanese Utility Model Publication No. HEI 7-16067 has the following problems.
First, since there are provided two motors and a planetary gear mechanism for transmitting the torque of the two motors, the structure is complex. Accordingly, the size of the range switching apparatus is increased.
Further, since two worm gears correspond to the two motors, the planetary gears and the ring gear are supported in a casing of the range switching apparatus and supported on a gear shaft which does not transmit power, the size of the range switching apparatus is further increased.
Further, the electric motor corresponding to a drive source is connected to an adsorbed disc in the electromagnetic clutch, and an adsorption rotor forming a magnetic field of the electromagnetic clutch is connected to a gear speed reduction mechanism in the side of a detent lever. Generally, since the adsorption rotor is formed so that the mass of the adsorption rotor is significantly greater than that of the adsorbed disc, an inertia of the adsorption rotor connected to the side of the detent lever is large even when the clutch is disengaged at a predetermined position, so that there is sometimes generated trouble in which the detent lever is rotated via the gear speed reduction mechanism due to an inertia force of the adsorption rotor so as to pass through the required shift range.
This tendency is significantly generated in the case where the driver operates the shift lever and drives the electric motor at a high speed so as to complete the range switching motion without delay and obtain a good shift feeling, and can not be ignored. That is because the revolution speed of the electromagnetic clutch connected to the electric motor becomes faster than the revolution speed of the electric motor and the inertia force of the adsorption rotor is increased that amount.
In order to solve the problems mentioned above, a method of adjusting a disengagement timing of the clutch is conceivable; however, if the inertia force of the adsorption rotor is large, it is necessary to disengage the clutch before a roller of the detent spring goes over a projection immediately before a range engagement groove formed so as to correspond to respective shift positions of the detent lever. In this case, it is indefinite whether or not the roller of the detent spring is securely received within a target range engagement groove, and the apparatus lacks reliability.
Further, since the position sensor in the apparatus switching the manual valve which is disclosed in Japanese Patent No. 2904290 is provided in the motor, only an angle of rotation of the motor can be detected. Accordingly, since it is impossible to directly detect the position of the range control shaft for operating the manual valve when disengaging the clutch, it is impossible to accurately control the switching position of the manual valve.
In view of the matters mentioned above, it is an object of the present invention to provide a compact range switching apparatus having a simple structure.
An object of the present invention is to provide a range switching apparatus of an automatic transmission which can reliably switch to a target range position, can realize a good shift feeling, and has high reliability.
An object of the present invention is to provide a range switching apparatus for reliably detecting a range switching position.
The invention as defined in claim 1 includes range switching means for switching a range; driving means for driving the range switching means; speed reducing means for reducing a drive force of the driving means and transmit the drive force to the range switching means; and a clutch for connecting and disconnecting a power transmitting state between the driving means and the speed reducing means, wherein a power output member of the clutch is connected to a power input member of the speed reducing means.
Accordingly, since the power output member of the clutch is directly connected to the power input member of the speed reducing means via no other members, it is possible to make the range switching apparatus compact.
Further, since the clutch is provided on the side of the driving means rather than on the side of the speed reducing means, a torque amplified by the speed reducing means is not applied to the clutch, so that a capacity of the clutch can be reduced and it is possible to make the range switching apparatus compact.
The invention as defined in claim 2 is dependent on claim 1, and further includes a position detecting sensor for detecting a range switching position of the range switching means between the range switching means and the speed reducing means.
Accordingly, since the range switching position of the range switching means is detected by the position detecting sensor between the range switching means and the speed reducing means, it is possible to reliably detect the switching position by the range switching means.
The invention as defined in claim 3 is dependent on claim 2, and is such that the position detecting sensor detects a motion of the power output member of the speed reducing means.
Accordingly, since the position detecting sensor detects the motion of the power output member in the speed reducing means, there is no effect from backlash of the speed reducing means so it is possible to increase the detecting accuracy of the position of the range switching means.
The invention as defined in claim 4 is dependent on claim 1 or claim 2, and is such that the clutch is an electromagnetic clutch having an adsorbed disc and an adsorption rotor with a mass greater than that of the adsorbed disc, the power output member of the clutch is made the adsorbed disc, and the power input member of the clutch is made the adsorption rotor.
Accordingly, since, among the adsorbed disc and the adsorption rotor having a mass greater than that of the adsorbed disc which constitute the electromagnetic clutch, the adsorbed disc, which has a small mass and is little affected by the inertia force accompanying the rotation, is connected to the range switching means and the adsorption rotor, which has a large mass and is greatly affected by the inertia force accompanying the rotation, is connected to the driving motor, it is possible to reliably and easily execute the range switching motion without being affected by the inertia force of the adsorption rotor. That is, it is possible to prevent in advance an erroneous operation, such as where the inertia force of the adsorption rotor is transmitted to the side of the range switching means so as to pass through the required range after the electromagnetic clutch is disengaged, thereby making it possible to increase the accuracy of switching the range.
Since it is possible to eliminate the influence of the inertia force of the adsorption rotor, it is possible to rotate the driving motor at a high speed, complete the range switching motion in a state where the possibility of the erroneous motion mentioned above is eliminated without delay after the driver operates the shift lever, and obtain a good shift feeling.
The invention as defined in claim 5 includes range switching means for switching a range; driving means for driving the range switching means; and a clutch for connecting and disconnecting a power transmitting state between the driving means and the range switching means. Further, the clutch has an adsorbed disc and an adsorption rotor having a mass greater than that of the adsorbed disc, the adsorbed disc is provided on the side of the range switching means, and the adsorption rotor is provided on the side of the driving means.
Accordingly, since, among the adsorbed disc and the adsorption rotor having a mass greater than that of the adsorbed disc which constitute the electromagnetic clutch, the adsorbed disc, which has a small mass and is little affected by the inertia force accompanying the rotation, is arranged on the side of the range switching means and the adsorption rotor, which has a large mass and is greatly affected by the inertia force accompanying the rotation, is arranged on the side of the driving motor, it is possible to reliably and easily execute the range switching motion without being affected by the inertia force of the adsorption rotor. That is, it is possible to prevent in advance an erroneous operation, such as where the inertia force of the adsorption rotor is transmitted to the side of the range switching means so as to pass through the required range after the electromagnetic clutch is disengaged, thereby making it possible to increase the accuracy of switching the range.
Since it is possible to eliminate the influence of the inertia force of the adsorption rotor, it is possible to rotate the driving motor at a high speed, complete the range switching motion in a state where the possibility of the erroneous motion mentioned above is eliminated without delay after the driver operates the shift lever, and obtain a good shift feeling.
The invention as defined in claim 6 is dependent on claim 5, and further includes a position detecting sensor for detecting a range switching position of the range switching means between the range switching means and the clutch.
Accordingly, since the range switching position of the range switching means is detected by the position detecting sensor between the range switching means and the clutch, it is possible to reliably detect the switching position by the range switching means.
The invention as defined in claim 7 includes range switching means for switching a range; driving means for driving the range switching means; a clutch for connecting and disconnecting a power transmitting state between the range switching means and the driving means; and a position detecting sensor for detecting the range switching position of the range switching means between the range switching means and the clutch.
Accordingly, since the range switching position of the range switching means is detected by the position detecting sensor between the range switching means and the clutch, it is possible to accurately detect the switching position by the range switching means.
The invention as defined in claim 8 is dependent on any one of claims 2, 6, or 7, and is such that the position detecting sensor detects a motion of the power input member (5a) of the range switching means.
Accordingly, since the position detecting sensor detects the motion of the power input member in the range switching means, there is no effect from backlash of the speed reducing means so it is possible to increase the detecting accuracy of the range switching means.
The invention as defined in claim 9 is dependent on any one of claims 1 through 8, and is such that the range switching means includes a detent mechanism for holding at each position corresponding to the range.
Accordingly, it is possible to securely hold the range switching position by the detent mechanism. Particularly, in the case that, among the adsorbed disc and the adsorption rotor having a mass greater than that of the adsorbed disc which constitute the electromagnetic clutch, the adsorbed disc, which has a small mass and is little affected by the inertia force accompanying the rotation, is connected to the range switching means and the adsorption rotor, which has a large mass and is greatly affected by the inertia force accompanying the rotation, is connected to the driving motor, it is possible to securely and easily hold the range switching position without being affected by the inertia force of the adsorption rotor. That is, it is possible to prevent in advance an erroneous operation, such as where the inertia force of the adsorption rotor is transmitted to the side of the range switching means so as to pass through the required range after the electromagnetic clutch is disengaged, thereby making it possible to increase the accuracy of switching the range.
Further, since it is possible to eliminate the influence of the inertia force of the adsorption rotor, it is possible to rotate the driving motor at a high speed, complete the range switching motion in a state where the possibility of the erroneous motion mentioned above is eliminated without delay after the driver operates the shift lever, and obtain a good shift feeling.
Further, in the case that the detent mechanism is, for example, as that of the conventional art, provided with a detent spring having an elasticity, a roller provided at a front end of the detent spring and a range engagement groove with which the roller is engaged, it is not necessary to execute a control of the clutch disengaging timing which is complex and lacks reliability so that the clutch is disengaged before the roller in the detent spring goes over the projection immediately before the range engagement groove formed so as to correspond to each of the shift positions of the detent lever, thus making it is possible to provide the range switching apparatus having a high reliability.
The invention as defined in claim 10 is dependent on any one of claims 2, 3, 6, 7, or 8, and further includes range selecting means for selecting the range; and range switching control means for operating and controlling the driving means and the clutch so as to make the range switching means execute a switching operation, thereby switching to a range selected by the range selecting means when a range switching position according to the range switching means which is detected by the position detecting sensor is different from a range selected by the range selecting means.
Accordingly, when the range switching position according to the range switching means which is detected by the position detecting sensor is different from the range selected by the range selecting means, the range selecting means operates and controls the driving means and the electromagnetic clutch so as to make the range switching means execute the switching operation, thus making it is possible to freely select a place for disposing the range selecting means.
The invention as defined in claim 11 is dependent on any one of claims 1 through 10, and is such that a casing of the apparatus is mounted to an automatic transmission and the clutch is arranged in a cover of the automatic transmission at a predetermined interval.
Accordingly, since the clutch is arranged apart from the cover of the automatic transmission by a predetermined gap, it is possible to prevent a situation in which a property of the clutch is changed due to heat generated by the automatic transmission and transmitted from the cover from occurring, such that a structure having high reliability can be achieved.
The invention as defined in claim 12 is dependent on any one of claims 1 through 11, and is such that the driving means is a driving motor, and a worm connected to the driving motor and a worm wheel connected to the power inputting member of the clutch are provided in an engaged state.
Accordingly, since the speed of rotation of the driving means is reduced by the worm and the worm wheel, the range switching means is not made to execute an extra switching operation via the clutch even when the driving means rotates somewhat excessively.
The invention as defined in claim 13 is dependent on any one of claims 1 through 12, and is such that the power inputting member of the clutch is connected to a hollow input shaft rotatably supported in the casing. Then, the power inputting member of the speed reducing means is inserted into the input shaft.
Accordingly, since the output shaft and the input shaft are arranged in a telescopic manner, it is possible to reduce the size of the apparatus in an axial direction so as to make the apparatus compact, arrange the output shaft and the input shaft in the same side with respect to the clutch, for example, on a right side in FIG. 2, arrange the speed reducing means and the driving motor in so as to be aligned on the same side such as the right side in FIG. 2 with respect to the clutch, and make the apparatus compact.
The invention as defined in claim 14 is dependent on any one of claims 1 through 13, and is such that the power input member of the speed reducing means is rotatably supported in the input shaft. Further, one end of the power input member is rotatably supported in the casing.
Accordingly, it is possible to securely support the power input member of the speed reducing means in the casing.
The invention as defined in claim 15 is dependent on any one of claims 1 through 4 or 9 through 14, and is such that the power input member of the speed reducing means has an input gear and a connection shaft. Further, the connection shaft has the input gear at one end, and both ends are supported in the casing and the input shaft by supporting members. Further, one supporting member is arranged at one end of the connection shaft so as to be supported in the casing, and another supporting member is supported in the input shaft.
Accordingly, it is possible to securely support the connection shaft of the speed reducing means in the casing.
The invention as defined in claim 16 is dependent on any one of claims 13 through 15, and is such that the input shaft has a worm wheel at one end and is supported in the casing.
Accordingly, it is possible to securely support the connection shaft in the casing and securely maintain engagement between the worm and the worm wheel.
The invention as defined in claim 17 is dependent on any one of claims 1 through 15, and is such that one supporting member among a plurality of supporting members of the connection shaft is arranged at a position overlapping with the worm wheel.
Accordingly, the supporting member is arranged on an inner peripheral side of the worm wheel, whereby it is possible to securely support the worm wheel.
The invention as defined in claim 18 is dependent on any one of claims 11, or 13 through 16, and is such that the power input member of the clutch is positioned at an end portion of the input shaft. Further, it is supported in the casing at a position between the power input member of the clutch and the worm wheel.
Accordingly, since the power input member of the clutch is positioned at the end portion of the input shaft and is supported in the casing at a position between the power input member of the clutch and the worm wheel, it is possible to support the driving motor and the clutch with an improved weight balance and stabilize the motion of the range switching apparatus.
The invention as defined in claim 19 is dependent on claim 1 or 11, and is such that the power input member of the speed reducing means is formed to be hollow and is rotatably supported in the casing. Further, an input shaft of the clutch having the power input member of the speed reducing means is inserted into the power input member.
Accordingly, since the power input member and the input shaft are arranged in a telescopic manner, it is possible to reduce the size of the apparatus in the axial direction so as to make the apparatus compact, arrange the power input member and the input shaft on the same side with respect to the clutch, for example, on the right side in FIG. 6, arrange the speed reducing means and the driving motor so as to be aligned on the same side such as the right side in FIG. 6 with respect to the clutch, and make the apparatus compact.
The invention as defined in claim 20 is dependent on claim 19, and is such that the input shaft of the clutch is rotatably supported in the power input member of the speed reducing means. Further, one end of the input shaft of the clutch is rotatably supported in the casing.
Accordingly, it is possible to securely support the power input member of the speed reducing means in the casing.
The invention as defined in claim 21 is dependent on claim 19 or 20, and is such that the input shaft of the clutch has a worm wheel arranged at one end and supporting members arranged on both sides of the worm wheel. Further, one supporting member is supported in the casing, and another supporting member is supported in the power input member of the speed reducing means.
Accordingly, it is possible to securely support the input shaft in the casing.
The invention as defined in claim 22 is dependent on any one of claims 19 through 21, and is such that the power input member of the speed reducing means has a hollow connection shaft and an input gear. Further, the connection shaft has the input gear at one end, is supported in the casing by a supporting member, and has a plurality of supporting members supporting the input shaft on an inner periphery.
Accordingly, it is possible to securely support the power input member of the speed reducing means in the input shaft.
The invention as defined in claim 23 is dependent on claim 22, and is such that one supporting member among a plurality of supporting members provided on the inner periphery of the connection shaft of the speed reducing means is arranged at a position overlapping with the input gear.
Accordingly, the supporting member is arranged on an inner peripheral side of the input gear, whereby it is possible to securely support the input gear.
The invention as defined in claim 24 is dependent on any one of claims 11, or 19 through 23, and is such that the connection shaft of the speed reducing means has an input gear at one end portion and has a power output member of the clutch at another end portion. Further, it is supported in the casing at a position between the input gear and the power output member of the clutch.
Accordingly, since the connection shaft of the speed reducing means has the input gear at one end portion, the power output member of the electromagnetic clutch at another end portion, and is supported in the casing at a position between the input gear and the power output member of the electromagnetic clutch, it is possible to support the driving motor and the clutch with an improved weight balance and stabilize the motion of the range switching apparatus.
The invention as defined in claim 25 is dependent on any one of claims 1 through 24, and is such that the range switching means operates a switching valve for switching a shift range of an automatic transmission.
Accordingly, the range switching apparatus can be provided in an automatic transmission to be mounted in a vehicle.